Handling apparatus for performing a tig weld with regulation of speed of the fed wire

ABSTRACT

A handling apparatus for performing a TIG weld comprises a main body for holding a filler rod; a feeding device attached to the main body and configured to advance the filler rod during welding; a control unit configured to act on the feeding device and to regulate the speed of the filler rod.

BACKGROUND

The subject matter of the present disclosure relates to a handlingapparatus for performing a TIG weld and arc welding kit, namely a set oftools that is used to perform a manual arc welding operation.

A known arc welding kit comprises a welding mask and a welding tool. Thewelding tool comprises an electrode. During welding operations, anelectric arc develops between the electrode and the welding area.

In a first type of arc welding, the SMAW (Shielded Metal Arc Welding),the electrode itself melts due to the heat developed by the electricarc, thus becoming the filler material in the weld. In a second type ofarc welding, the TIG (Tungsten Inert Gas), the electrode is solid, andthe filler material is provided separately.

With more detail, the kit comprises a set of sensors which can detectthe main operating parameters of a welding process, namely the voltage(V), the current (A), the welding speed (W) and their combination tocalculate the heat input. The welding mask can be provided with adisplay device so that these parameters can be shown to a welder,thereby providing him with a possibility of correcting the welding inreal time. An example of this welding mask is the one shown in the U.S.Pat. No. 6,242,711 81.

A disadvantage of the known welding kit is that it merely provides thewelder with the welding parameters. However, this does not guaranteethat the welder can adapt and correct a welding that is being performedimproperly. In other words, the welding operation itself still reliesheavily on the manual skill of the operator. This is particularly truewith respect to the welding voltage, since it is mainly determined bythe distance of the electrode from the weld area.

SUMMARY

An embodiment of the invention therefore relates to a handling apparatusfor performing a TIG weld. Such handling apparatus comprises a main bodyfor holding a filler rod. The handling apparatus also comprises afeeding device attached to the main body and configured to advance thefiller rod during welding. A control unit is configured to act on thefeeding device and to regulate the speed of the filler rod.

In an embodiment, this may be advantageous in helping the welder tospread more evenly the filler material during the TIG weld. Therefore,this gives more aid to the welder in case of a TIG weld, which is one ofthe most difficult type of weld.

Another embodiment of the present invention relates to an arc weldingkit. The kit comprises the above described handling apparatus. The kitalso comprises a welding tool with a main body and a handle attached tothe main body so that it can be held by a welder. The kit also comprisesa non-consumable electrode for performing a TIG weld. The electrode isattached to the main body. An adjusting device is associated with theelectrode for moving the electrode forward/backward with respect to themain body of the welding tool. The control unit is also connected to theadjusting device, and is configured to act on the adjusting device formaintaining a substantially constant distance between the electrode anda weld area.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and specific embodiments will refer to the attacheddrawings, in which:

FIG. 1 is a schematic representation of an arc welding kit according toan embodiment;

FIG. 2 is a side sectional view of a component of the kit of FIG. 1;

FIG. 3 is a front sectional view of the component of FIG. 2;

FIG. 4 is a side sectional view of a component of the kit of FIG. 1,according to a different embodiment;

FIG. 5 is a side sectional view of a handling apparatus for performing aTIG weld according to an embodiment;

FIG. 6 is a top sectional view of the handling apparatus of FIG. 5;

FIG. 6A is an enlarged view of a detail of FIG. 6;

FIG. 7 is a front sectional view of the handling apparatus of FIGS. 5and 6;

FIG. 8 is a front view of a further component of the kit of FIG. 1; and

FIG. 9 is a schematic representation of the functioning of the kit ofFIG. 1.

DETAILED DESCRIPTION

The following description of exemplary embodiments refer to theaccompanying drawings. The same reference numbers in different drawingsidentify the same or similar elements. The following detaileddescription does not limit the invention. Instead, the scope of theinvention is defined by the appended claims.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the subject matter disclosed. Thus, theappearance of the phrases “in one embodiment” or “in an embodiment” invarious places throughout the specification is not necessarily referringto the same embodiment. Further, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreembodiments. With reference to the attached drawings, with the number 1is indicated an arc welding kit according to an embodiment of thepresent invention.

The welding kit 1 comprises a welding tool 2, which is configured to beheld by a welder.

The welding tool 2 comprises an electrode 3. In one embodiment, which isused to perform a SMAW (shielded metal arc weld), shown in FIGS. 2 and3, the electrode 3 is consumable. In other words, in this embodiment theelectrode 3 becomes the filler material of the weld. In a secondembodiment, shown in FIG. 4, the electrode 3 is non-consumable, thus itis used to perform a TIG (Tungsten Inert Gas) weld.

With additional details, the welding tool 2 comprises a main body 20,configured to support the electrode 3. The main body 20 is, in anembodiment, axial- symmetric, and develops mainly along a longitudinalaxis “A”. A handle 21 for the welder supports the main body 20.

The main body 20 has a seat 20 a in which the electrode 3 is installed.As shown in FIGS. 2 and 4, the welding tool 2 is provided with bearings22, which are attached to the main body and located in proximity of theseat 20, so that they can support the electrode 3 and allow it to moveforward and backward. In other words, the electrode 3 can move forwardand backward inside the seat 20 a by sliding on the bearings 22.

Also, the welding tool 2 comprises an adjusting device 4 associated withthe electrode 3, in order to move the electrode forward/backward withrespect to the main body 20. The adjusting device 4 comprises a wheel 23having a central axis “C” disposed transversally and, in an embodiment,perpendicularly, to the longitudinal axis “A” of the electrode 3, whichis parallel to the axis of the main body 20. Indeed, the main body 20 isprovided with a port in which the wheel 24 is inserted.

In operation, the rim of the wheel 23 is in contact with the electrode 3so that the electrode 3 can be moved along the longitudinal axis “A” bya rotation of the wheel along the central axis “C”. The adjusting device4 also comprises a motor 24. Such motor 24 is, in an embodiment,electric. In an additional embodiment, the motor is an electromagneticmotor, and is installed on the wheel 23 in order to actuate the wheel 23and through it, the electrode 3.

With particular reference to the SMAW welding tool 2 of FIG. 2 pleasenote that, in use, the wheel 23 advances overtime since the electrode 3is consumed during welding. Therefore, the rotation speed of the motor24 provides an overall forward movement to the electrode, and varies therotation speed in order to adjust the distance of the tip of theelectrode 3 as will be explained in a following part of the disclosure.

On the other hand, in the TIG welding tool 2 of FIG. 4 the electrode 3is not consumed during welding. Therefore, the wheel 23 is moved only toadjust the distance of the electrode 3.

Also, in the embodiment of FIG. 4 a source of inert gas is present (notshown in the drawings) in order to shield the tip of the electrode 3 andthe weld area from atmospheric oxygen. This source of inert gas is byitself known to the person skilled in the art, thus will not bedescribed in detail. The kit 1 comprises a voltage sensor 5 which isconfigured to detect a welding voltage “Vw” between the electrode 3 andthe weld area, that is function of the distance between the end of theelectrode facing the work piece and the weld area of the work piece. Thevoltage sensor 5 is also configured to emit a voltage signal “Vs”, whichis representative of a value of the welding voltage “Vw”. Such voltagesensor 5 can be of any type known to the person skilled in the art, andtherefore will not be described in detail.

The kit 1 also comprises a control unit 6. In the following part of thedisclosure, the control unit 6 will be described by subdividing it intoa plurality of modules. Such subdivision is done for ease of descriptiononly, and in no way, should be considered as reflecting the physicalstructure of the control unit 6 itself. Rather, each module can beimplemented as an electronic circuit on a suitable hardware support, asa software routine, subroutine or library or as both. Each module mayreside on a local unit or may be distributed over a network. Also, themodules can communicate with each other either via a suitable wired orwireless protocol.

The control unit 6 comprises a data acquisition module 7, which isconfigured to acquire the above-mentioned voltage signal “Vw”.

The control unit 6 also comprises a memory module 16, which isconfigured to store a target voltage value “Vt”.

The control unit 6 also comprises an input module 17 configured to setsaid target voltage value “Vt” in said memory module 16. In a particularembodiment of the invention the input module 17 can be a QR code reader.In this way, the voltage “Vt”, as well as any other parameter related tothe welding process, can be read by the input module 17 on a suitablyencoded QR code.

The control unit 6 also comprises a processing module 8, which isconfigured to output an actuation signal “Sa” function of at least thevoltage signal “Vs”. Also, the processing module 8 is configured toretrieve the target voltage value “Vt” and to compare it with thewelding voltage value “Vw”. The actuation signal “Sa” is therefore atleast in part directly proportional to the result of such comparison.With additional detail, the processing module 8 may be programmed with aPID (Proportional, Integral and Derivative) logic. Therefore, theactuation signal “Sa” may be the sum of a part directly proportional tothe difference between “Vw” and Vt”, of a part proportional to thederivative of such difference and of a part proportional to the integralof such difference. Any possible combination can be used, depending onthe chosen control strategy. The processing module 8 can also beconfigured to supply a voltage difference signal “Dv” representing theresult of the difference between “Vw” and “Vt”.

The control unit 6 also comprises an actuation module 14 connected tothe adjusting device 4. The actuation module 14 is configured to operatethe adjusting device 4 as directed by the actuation signal “Sa”. Inparticular, the actuation module 14 operates the motor 24 which rotatesthe wheel 23. Optionally, the welding kit also comprises a welding mask9. Such welding mask 9 is configured to be worn by a welder during awelding process as a standard safety mask. In particular, the weldingmask 9 comprises a darkened window 10 from which the welder may observethe welding process without being blinded by the intense light.

Additionally, the welding mask 9 is provided with a welding velocitysensor. The welding velocity sensor 11 is configured to detect a.welding velocity “Wa”, and to emit a welding velocity signal “Ws”representing a value of the welding velocity “Wa”.

According to an embodiment of the invention, the welding velocity sensor11 comprises a first optical sensor 12A. The first optical sensor 12A isin particular arranged so that, during welding operation it faces theweld area. As shown in FIG. 8, the first optical sensor is, in anembodiment, placed on the external surface of the welding mask 9, overthe darkened window 10. The welding velocity sensor 11 also comprises areference frame sensor 12B, in an embodiment. This reference framesensor 12B can be any kind of sensor which is able to detect a motionwithin a fixed frame of reference. For example, the reference framesensor 12B can be an inertial sensor located on any point of the weldingmask 9.

With more detail, in the embodiment shown in FIG. 8 the reference framesensor 12B is a second optical sensor. The reference frame sensor 12B istherefore, in an embodiment, arranged to face a fixed reference scene inthe environment, as for example the work piece part from the weld area,and placed. In an embodiment, it is placed beside the first opticalsensor 12A. In an embodiment of the invention, the sensors 12A, 12B areimaging cameras.

With additional detail, the first optical sensor 12A is configured todetect the velocity of the welding pool relative to itself Also, thereference frame sensor 12B is configured to detect the velocity of theabove mentioned fixed reference scene. According to one embodiment, thewelding velocity sensor also comprises a velocity computing module 13which is configured to compute the welding velocity “Wa” as a differencebetween the velocities detected by the second 12B and the first opticalsensor 12A. Alternatively, the first optical sensor 12A and referenceframe sensor 12B both transmit the respective velocities to the controlunit 6, in particular to the data acquisition module 14.

The processing module 8 is also configured to compute a velocitydifference between the welding velocity “Wa” and a target velocity “Wt”value, said processing unit being configured to emit a velocitydifference signal “Ow” representing the result of said velocitydifference.

Optionally, the welding mask 9 comprises a visualization device 15. Suchvisualization device 15 is arranged to be easily visible by the welderduring the welding process. As shown in FIGS. 1 and 8, the visualizationdevice 15 is placed inside the welding mask 9, in an embodiment on oneside of the darkened window 10.

With more detail, the visualization device 15 is configured to acquirethe above-mentioned velocity difference signal “Dw”, thus showing arepresentation of the velocity difference to the welder. Similarly, thevisualization device 15 can be configured to acquire the voltagedifference signal “Dv” mentioned above and to show a representation ofthe voltage difference to the welder.

In an embodiment, the visualization device 15 can be configured to showan operating parameter of the welding process, such as the voltage (V),the current (A), the welding speed (W), respectively between theelectrode and the weld area, or their combinations. As shownschematically in FIG. 8, the visualization device comprises a pluralityof LEDs 26. These LEDs are arranged in a cross, and are configured tolighten in such a way as to indicate whether the welder should go fasteror slower, or if he should get nearer or farther from the weld area, inan embodiment.

Referring specifically to FIGS. 5 and 6, the kit 1 can also comprises ahandling apparatus 18 for a filler rod “R”. The handling apparatus 18comprises a feeding device 19 configured to advance the filler rod “R”during welding.

With additional details, the handling apparatus 18 comprises a main body27, configured to support the filler rod “R”. The main body 27 is, in anembodiment, axial-symmetric, and develops mainly along a longitudinalaxis “B”. A handle 28 for the welder is attached to the main body 27. Inan embodiment, the handle 28 surrounds the main body 27 of the handlingapparatus 18.

The main body 27 has a central seat 27A in which the filler rod “R” isplaced. As shown in FIG. 5, the handling apparatus 18 is provided withbearings 29, which are attached to the main body 27 and located inproximity of the central seat 27A, to support the filler rod “R” andallow it to move forward/backward. In other words, the filler rod “R”can move forward/backward inside the seat 27A by sliding on the bearings29.

The feeding device 19 comprises a wheel 30 having a central axis “D”disposed transversally, and, in an embodiment, perpendicularly to thelongitudinal axis “B” of the main body 27.

In operation, the rim of the wheel 30 is in contact with the filler rod“R” so that it can be moved along the longitudinal axis “B” by arotation of the wheel 30 along the central axis “D”. The feeding device19 also comprises a motor 31. Such motor 31 is electric, in anembodiment, and is installed on the wheel 30 in order to actuate thefiller rod “R”.

In an alternative embodiment, not shown in the drawings, the feedingdevice 19 comprises an electromagnetic actuation device for the fillerrodn “R” instead of the wheel 30 and the motor 31.

If the handling apparatus 18 is used, the processing module 8 may beconfigured to emit a feeding velocity signal “Sv” to the actuationmodule 14. The feeding velocity signal “Sv” is proportional to a feedingvelocity value “Fv”, in an embodiment. The actuation module 14 istherefore also configured to operate the feeding device 19 of thehandling apparatus 18 as directed by the feeding velocity signal “Sv”.

Also, as shown in FIG. 6a , the handling apparatus 18 comprises acontrol interface 32 associated with the processing module 8. Thecontrol interface 32 is configured to emit a command signal “Cv” to theprocessing module 8, so that the welder can increase or decrease thefeeding velocity signal “Sa”.

With additional detail, the control interface 32 comprises a button 33placed on the handle 28. Specifically, the button 33 allows the welderto adjust the feeding velocity continuously; however, the button 33 isdesigned as to give a tactile feedback in the form of “clicks” atpredetermined intervals so that the welder can be made aware with acertain precision of the amount that the feeding velocity is beingmanually increased or decreased.

This written description uses examples to disclose the invention,including the preferred embodiments, and also to enable any personskilled in the art to practice the invention, including making and usingany devices or systems and performing any incorporated methods. Thepatentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those skilled in the art. Suchother examples are intended to be within the scope of the claims if theyhave structural elements that do not differ from the literal language ofthe claims, or if they include equivalent structural elements withinsubstantial differences from the literal languages of the claims.

What is claimed is:
 1. A handling apparatus for performing a TIG weld,the handling apparatus comprising; a main body for holding a filler rod;a feeding device attached to the main body and configured to advance thefiller rod during welding; and a control unit configured to act on thefeeding device and to regulate the speed of the filler rod.
 2. Thehandling according to claim 1, wherein the control unit comprises aprocessing module configured to emit a feeding velocity signalproportional to a feeding velocity value; an actuation module connectedto the feeding device configured to operate the feeding device asdirected by the feeding velocity signal.
 3. The handling apparatusaccording to claim 2, further comprising a control interface associatedto the processing module and configured to emit a command signal to theprocessing module in order to increase or decrease the feeding velocitysignal as directed.
 4. The handling apparatus according to claim 3,further comprising a handle configured to be manually held, the controlinterface comprising a button placed on the handle.
 5. The handlingapparatus according to claim 4, wherein the button is configured to givea tactile feedback at predetermined levels of the feeding velocitysignal.
 6. The handling apparatus according to claim 1, wherein thefeeding device comprises a wheel attached to the main body, the rim ofthe wheel being configured to be placed in contact with the filler rodto move the filler rod along a longitudinal axis of the main body by arotation of the wheel.
 7. The handling apparatus according to claim 6,wherein the feeding device further comprises a motor, connected to thewheel for moving the filler rod.
 8. The handling apparatus according toclaim 1, wherein the feeding device comprises an electromagneticactuation device for the filler rod.
 9. An arc welding kit, the arcwelding kit comprising: an handling apparatus comprising a main body forholding a filler rod, a feeding device attached to the main body andconfigured to advance the filler rod during welding and a control unitconfigured to act on the feeding device and to regulate the speed of thefiller rod according to; a welding tool comprising a main body; a handleattached to the main body; and a non-consumable electrode for performinga TIG weld, the electrode being attached to the main body an adjustingdevice associated with the electrode for moving the electrodeforward/backward with respect to the main body of the welding tool; thecontrol unit being connected to the adjusting device and configured toact on the adjusting device for maintaining a substantially constantdistance between the electrode and a weld area.
 10. The arc welding kitaccording to claim 9, further comprising a welding assistance devicecomprising a welding mask, a visualization device attached to thewelding mask and arranged to show a representation of at least aperformance of a welding operation selected from: welding speed,voltage, current, respectively between the electrode and the weld area.11. The arc welding kit according to the previous claim 10, wherein thewelding mask further comprises a welding velocity sensor attached on thewelding mask, the welding velocity sensor being configured to detect awelding velocity; the visualization device being arranged to show arepresentation of the welding velocity and of consequent heat input. 12.The handling apparatus according to claim 7, wherein the motor is anelectric, electromagnetic motor.